Quizzer is a webserver for collaborative writing lab support. Based on a _fail early, fail often? approach to written language, the tool is particularly suited to second-language learners. The workflow (essay - error - quiz - exam) treats mistakes as an opportunity for learning, and emphasizes rapid pattern-practice iterations based on student writing samples. This approach makes more efficient use of staff time than the traditional essay-and-appraisal approach. So that's the pitch -- give it a try.